This collection of articles on ¿Work?ows for e-Science¿ is very timely and - portant. Increasingly, to attack the next generation of scienti?c problems, multidisciplinary and distributed teams of scientists need to collaborate to make progress on these new ¿Grand Challenges¿. Scientists now need to access and exploit computational resources and databases that are geographically distributed through theuseof high speed networks. ¿Virtual Organizations¿ or ¿VOs¿ must be established that span multiple administrative domains and/or institutions and which can provide appropriate authentication and author- ation services and access controls to collaborating members. Some of these VOsmayonlyhavea?eetingexistencebutthelifetimeofothersmayrun into many years. The Grid community is attempting to develop both sta- ards and middleware to enable both scientists and industry to build such VOs routinely and robustly. This, of course, has been the goal of research in distributed computing for many years; but now these technologies come with a new twist service orie- ation. By specifying resources in terms of a service description, rather than allowing direct access to the resources, the IT industry believes that such an approach results in the construction of more robust distributed systems. The industry has therefore united around web services as the standard technology toimplementsuchserviceorientedarchitecturesandtoensureinteroperability between di?erent vendor systems.